8-71 Weiand Install - Going Big

We add an 8-71 Weiand blower to our 383

It might be the current economic situation, or possibly because it's an election year or maybe we have all just taken a good look at our waistline, but America seems to minimizing their propensity for super sizing. Small is the new big, with a call to arms to shrink everything from the government right down to the size of a New Yorker's favorite carbonated beverage.

One might question the logic behind imposing limits on a Big Gulp, but who among us wouldn't like to drop a few pounds? In many cases, less really is more, but this particular build up isn't one of those instances. In fact, it's all about more, as in more cubes, more cam and more compression--but we didn't stop there. In keeping with the theme, we even added a large blower. Usually reserved for big-block applications, our big-inch, small-block was topped with nothing less than a dual-quad inducted, 8-71 supercharger from Weiand. Loud and proud, nothing screams "look at me" like an 8-71 sticking out of the hood. The question now was did the massive blower have the bite to back the bark? Was it really worth the effort to "Go Big?"

While it is possible to build small-blocks exceeding 450 inches, doing so requires a great many custom components. Our adventure was more of an off-the-shelf variety, including the eventual displacement of our stroker assembly. Not content with a mere 350 inches, we stepped up to the most common of all small-block stroker dimensions, 383 ci. This was achieved in the usual fashion, by combining a 4.03-inch bore with a 3.75-inch stroke. Knowing boost was also on the list, we opted for a 4340 forged steel stroker crank from Scat matched with a set of its 6.0-inch I-beam rods.

Completing the stroker rotating assembly was a set of forged flat-top pistons from JE and matching rings. Some may question the use of (relatively) high-compression flat-top pistons on a blower motor, but elevated static compression improves off-boost power and fuel economy, to say nothing of maximizing overall power. The trade of is it makes octane rating and tuning more critical. Not wanting to use a production block, we instead chose a new four-bolt race block from Procomp Electronics. Available with either a 4.030- or 4.125-inch bore, we chose the smaller of the two. The beefy block was on hand to withstand the prodigious power offered by the blown stroker.

The camshaft all but determines the personality or more accurately the power curve of the motor. Small cams maximize low-speed power (torque) production, while more aggressive profiles shift power production higher in the rev range. Looking for big power numbers from our 383, we chose our cam accordingly. Choosing a cam from the Crane catalog, we selected one of its powerful solid roller profiles. The Crane cam offered a 0.670/0.625 lift split, a 260/268 duration split and 108-degree lobe separation angle.

We know blower cam guys out there might be wondering where the big intake-to-exhaust split or where the wide LSA are, but believe us, this cam worked well both normally aspirated and supercharged. We've even tested this profile against a so-called blower grind and found the NA cam worked better in both applications. The high-lift, roller cam was ideally suited to the impressive flow rates offered by our cylinder heads. Crane also supplied the roller lifters and 1.5 ratio Gold roller rockers. With our cubes, cam and compression taken care of, it was time to address the induction system. Obviously the stroker would eventually be topped by the massive 8-71 supercharger from Weiand, but we also wanted to break in the motor and make a few pulls in normally aspirated guise to establish a baseline. Looking to optimize the induction system, we combined a set of Super 23 230 heads from Trick Flow Specialties with a single-plane intake from Dart.

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8-71 Weiand Install - Going Big

15 Run on the dyno, the 8-71 blown stroker thumped out some serious power, eclipsing 728 hp at 7.8 psi, 760 hp at 8.7 psi then 813 hp at 11.4 psi. Increasing the blower speed relative to the engine increased the boost pressure and eventual power output. The 813-hp version required 100-octane race fuel, but could easily be run at the lower boost levels on pump gas (which we did).

1 Since we had big power in mind for our stroker, we elected to try a new 4-bolt race block from Procomp Electronics. Offered in both 4.030- and 4.125-inch bore variations, the beefy 4-bolt block represented a serious step up the stout scale. We chose the 4.030-inch bore block to produce our 383.

2 The block was stuffed full of a forged rotating assembly that consisted of a 4340 forged steel, 3.75-inch Scat crank and matching 6.0-inch forged steel connecting rods.

3 The bottom end also featured a HV/HP billet oil pump from Moroso secured by an ARP oil pump stud. The integrated oil pump pick up required a dedicated oil pan, also supplied by Moroso.

4 JE supplied a set of flat-top pistons with valve reliefs for our sizable Crane cam profile. The flat-top pistons combined with 70cc heads to produce a static compression ratio of 10.3:1. Sealing the heads was a set of Fel Pro head gaskets and ARP head studs.

5 Crane Cams' aggressive roller profile offered a 0.670/ 0.625 lift split, a 260/268-degree duration split and tight 108-degree LSA. While this might not sound like a traditional blower cam, it worked well both NA and supercharged.

6 To ensure maximum head flow, we went with Trick Flow Specialties' Super 23 230 heads for use on our stroker. According to Trick Flow's literature, the 230cc intake ports are as close as you can get to the performance offered by the 18-degree race heads and still retain all the components of the traditional 23-degree small-block.

7 Advertised with a 2.08/1.60 stainless steel valve package, the Trick Flow heads also featured 70cc combustion chambers. Ours actually measured right near 72cc, which brought the static compression ratio to 10.3:1.

8 Riding on top to the titanium retainers was a set of 1.5-ratio Crane Gold roller rockers.

9 Prior to running the 383 stroker with the 8-71 Weiand blower, we decided to break it in and dyno test the combination in normally aspirated trim. The stroker was equipped with a Dart single-plane intake and Holley 950 HP carburetor.

10 MSD supplied the billet (small cap) distributor and plug wires. Both the normally aspirated and supercharged combinations were run with an MSD Digital 7 ignition amplifier.

11 Exhaust chores were handled by a set of 1 3/4-inch Hooker sprint car headers.

12 After a break in procedure, the Crane-cammed 383 stroker pumped out some impressive power. With the proper jetting and timing and reducing the amount of oil in the pan by 1 quart, the 383 produced 571 hp at 6,600 rpm and 497 lb-ft of torque at 4,900 rpm on 91-octane pump gas.

13 Nothing says, "I mean business" like a massive 8-71 Weiand supercharger sticking out of the hood. Usually relegated to big-block duty, it was perfect for our powerful big-inch Mouse.

14 Boost pressure supplied by the blower was determined by the ratio (tooth count) between the crank and blower pulleys. Carburetion was via a pair of 750 HP carburetors and dual-carb linkage from Holley.

15 Run on the dyno, the 8-71 blown stroker thumped out some serious power, eclipsing 728 hp at 7.8 psi, 760 hp at 8.7 psi then 813 hp at 11.4 psi. Increasing the blower speed relative to the engine increased the boost pressure and eventual power output. The 813-hp version required 100-octane race fuel, but could easily be run at the lower boost levels on pump gas (which we did).

16 Looking to increase the power output of your normally aspirated stroker? Looking to make a serious performance statement? Blowers are cool, and big blowers like the Weaind 8-71 use on this 383 stroker are even more so. Not only do they look badass sticking out of the hood, but they are capable of some serious power on the right combination. Adding the 8-71 blower to this small-block increased the power output from 571 hp to 813 hp at just over 11 psi. Note that the curve was still climbing and the 8-71 had plenty of boost left in reserve. At the elevated boost levels, you might think about a CryO2 system from Design Engineering Inc. (DEI), which can significantly reduce inlet temperatures and allow you to run pump gas.

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